Verification of acoustic emission testing of floor conditions in aboveground tanks by comparison of acoustic emission data and floor scan testing

Acoustic emission testing based on test procedure, database and evaluation criteria has been widely used as a standard method for testing floor conditions in aboveground tanks. More than 160 tanks have been tested in Japan on the basis of the test procedure since it was introduced to Japanese industry in 1999. After acoustic emission testing, tanks were opened and thickness data were collected. Good correlation has been found between acoustic emission activity and the corrosion risk parameter (representing corrosion rate) resulting from a statistical analysis of the thickness data from discrete point thickness measurement. Ultrasonic floor scan testing 0 6 cases) and magnetic flux leakage floor scan testing (one case) have been conducted to verify the reliability of the correlation. This paper presents some case studies, comparing the acoustic emission data with floor scan testing results. The reliability of acoustic emission testing in terms of source location and thickness mapping is discussed with the aid of location figures. The case studies have been made partly as a joint research project organized by the National Research Institute of Fire and Disaster, partly as the research project of the High Pressure Institute of Japan, sponsored by the Japan Oil, Gas and Metals National Corporation.